Configurations proposal, take n
ross at soi.city.ac.uk
Wed Nov 29 07:28:45 EST 2006
A few questions about package versions:
Presumably it will be possible to have multiple Build-Depends lines,
to allow different interactions to be treated separately. Will it
be possible to constrain the same package in more than one of these?
build-depends: base < 2, fps >= 0.8
build-depends: base >= 1.5, mtl
(It's possible that no solution will exist, but that's nothing new.)
At present Haskell import declarations cannot specify package versions,
so it is reasonable to assume that a single version of a prerequisite
package satisfies the dependencies of our package. That's only for
direct dependencies: it's fine (with GHC) to depend on packages P and Q,
where each of these depends on a different version of package R.
Flags allow the builder to force a particular configuration even if
others would work on the build system, but do they have sufficiently
fine granularity? The build system might have versions 1.2 and 1.3 of
a package, either of which would satisfy the given dependency, but the
target system has only 1.2.
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